This invention pertains generally to scales and more particularly to a counting scale for determining the number of articles in a group.
Heretofore, there have been some attempts to expedite the counting of large numbers of articles, such as electronic components and other small parts, by first weighing a known quantity or sample to determine the average weight of the articles, then weighing the unknown quantity and combining the weights to determine the number of articles. In order to provide sufficient resolution to accurately determine the weight of the sample and sufficient range to measure anything but a very small unknown quantity, it has generally been necessary to use two separate scales, one a low capacity scale for weighing the sample and the other a high capacity scale for weighing the unknown quantity.
The use of two scales has a number of obvious disadvantages. In addition to the inconvenience of having to work with two scales and make two separate readings, both scales must be calibrated to a high degree of accuracy. This can be difficult, particularly with electronic scales utilizing amplifiers which are seldom perfectly linear in practice. In addition, there are operational problems such as determining whether the sample should be added to the unknown quantity before the latter is weighed.